Cascaded Multilevel Structure With Three-Phase and Single-Phase H-Bridges for Open-End Winding Induction Motor Drive

A new multilevel topology for an open-end winding motor drive is proposed in this article, presenting a similar structure to the cascaded H-bridge multilevel inverter. The proposed topology combines three-phase and single-phase conventional H-bridge voltage source inverters. The topology is flexible, allowing to increase the number of voltage levels through the simple integration of new single-phase H-bridge inverters connected in wye. Based on this topology, it is possible to obtain two different configurations. These modular multilevel topologies can be easily extended, both in terms of voltage level and the number of voltage levels. The topology is characterized by the capability to a supply higher voltage to the motor windings or use lower dc voltages when compared with classical solutions. Well-known modulation schemes, such as the multilevel sinusoidal pulsewidth modulation technique, can be easily adapted to the proposed topology. The operation and characteristics of the two configurations for the proposed multilevel topology are confirmed by several experimental tests realized through a laboratory prototype.